It is known that a variety of compounds have fungistatic properties and can therefore be used to inhibit the growth of fungi in a product. However, many fungistatic compounds are generally not accepted in food products or they have a non-natural image.
WO 97/16973 (Unilever) discloses compositions suitable for combating fungi in food and other products such as personal care products, comprising the combination of a fungal cell wall lytic enzyme and a natural microbial membrane affecting substance (MMAS), in an effective concentration. The preferred enzymes are chitinase, .beta.-(1,3)-glucanase and .beta.-(1,6)-glucanase. The MMAS is exemplified by nisin, amphiphilic alpha-helix forming peptides, such as histatins and the polypeptide FASLLGKALKALAFQ (=Phe-Ala-Ser-Leu-Leu-Gly-Lys-Ala-Leu-Lys-Ala-Leu-Ala-Lys-Gln) (SEQ ID No:1), and fungal inhibitors, such as carvacrol and sorbic acid. MMAS are present in herbs suitable for food preparation and also herbs suitable for cheese manufacture, especially chives, curcuma and garlic.
However, further research has shown that the fungistatic compounds described in WO 97/16973 are not always heat stable so that they become partly or completely inactivated when the products incorporating them are heated to achieve pasteurisation or even sterilisation.
WO 97/14310 describes the combination of saccharides in general with biocidal active component for combating plant pathogens.
EP 867125 describes combinations of water-soluble hemicellulose in general with a component from a range of preservatives, for preserving food and drinks.
WO 93/04588 discloses combinations of chelating agents and lanthionines (amongst which is nisin) as antimicrobial compositions. Among the chelating agents are mentioned polyols, saccharides, polyethylene glycol.
JP 63/185358 describes combinations of starch hydrolysates with one of glycine, maltose, ethanol, sorbic acid, lysozyme, edible salts of acetic acid for preservation.
Chemical Abstracts 116 (11), Mar. 16, 1992 (Kurusawa et al) describe the induction of cellulase by .beta.-gentiobiose.
Thus, in spite of the success of the approach described above, there is still a need for fungistatic compounds that are sufficiently heat-stable in addition to being acceptable in food products and other products that come in contact with humans, such as personal care products.